Esters acyl chlorides

Ammonolysis. Reactions involving ammonia. Ammonolysis of esters, acyl chlorides, and anhydrides give amides aniline is produced by ammonolysis of chlorobenzene. The reaction is analogous to hydrolysis, with ammonia substituted for water. 

In Chapter 9 you see the basic structure of each of the carboxylic acids and Ccirboxylic acid derivatives. In this chapter we focus on the carboxylic acids and related compounds, such as esters, acyl chlorides, and acid anhydrides, and we also include some information on amides (see Chapter 13 for an additional examination of cimides). Before you can get into synthesis and reactions, though, you need to understand the structure and nomenclature of these compounds. 

Reaction XIV. (b) Action of Magnesium Alkyl or Aryl Halide on Esters, Acyl Chlorides, and Acid Anhydrides. (C., 1901,1., 725 II., 622 1902, I., 1411.)—In all the above cases tertiary alcohols are obtained, except, of course, in the case of- formic esters when secondary alcohols are formed. Using esters, the reaction has a wide application, as the examples given below show the use of the acyl chlorides and anhydrides is only of theoretical interest. The reactions in all cases take the usual Grignard course. 

Acid esters are useful synthetic intermediates. For example, their use in the synthesis of long-chain dicarboxylic esters by electrolytic (anodic) synthesis has already been noted (Expt 5.131). Furthermore the reaction of the acid ester with thionyl chloride in the usual way will convert the carboxylic acid grouping to an acyl chloride group thus yielding the synthetically useful ester-acyl chloride the products are usually purified by distillation under reduced pressure. 

One of the uses of these ester-acyl chlorides is for the synthesis of co-hydroxy esters which involves the selective reduction of the acyl chloride grouping with sodium borohydride161 the alkoxycarbonyl group is unaffected by this metal hydride reducing agent (cf. Section 5.4.1, p. 519). 

In the initial studies about the reaction of /V.zV-disubstituted formamides with alkaline metals to give glyoxylic amides, the participation of carbamoyl metal derivatives as intermediates was postulated83. The first preparation of the carbamoyllithium 77 was described two years later by a mercury-lithium transmetallation from compound 76 at —75 °C (Scheme 20)84. The authors proposed also an aminocarbene structure 78 and studied its reactivity with methanol, methyl iodide, carbonyl compounds, esters, acyl chlorides, mercury(II) chloride and tri-n-butyltin chloride providing compounds 79. 

In fact, it is difficult to avoid these products when the a-halo dicat-boxylic acid is desired. Preparation of the monohalogenated compounds is accomplished by treatment of the ester acyl chloride with bromine or sulfutyl chloride in thionyl chloride solution (88-98%). ... 

Esters, acyl chlorides, and anhydrides usually react with 2 mol of Grignard reagents to lead to alcohols [Eqs. (9) and (10)] ... 

The other is a two-step, elimination-addition mechanism. In the elimination step, / elimination occurs by an E2 mechanism to give a ketene, a very reactive compound that is not usually isolable. In the addition step, the alkoxide adds to the electrophilic carbonyl C of the ketene to give the enolate of an ester. Acyl chlorides lacking a-hydrogens (t-BuCOCl, ArCOCl), of course, can react only by the addition-elimination mechanism. 

The most common O- and N-acylation procedures use acylating agents that are more reactive than carboxylic acids or their esters. Acyl chlorides and anhydrides react rapidly with most unhindered alcohols and amines to give esters and amides, respectively. 

Esters, acyl chlorides, and amides are called carboxylic acid derivatives because they differ from a carboxylic acid only in the nature of the group or atom that has replaced the OH group of the carboxylic acid. 

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